Electrical tracking resistance compositions, articles formed therefrom, and methods of manufacture thereof

ABSTRACT

A composition comprises, based on the total weight of the composition, 25 wt % to 50 wt % of a polyetherimide; and 50 wt % to 75 wt % of a polyphthalamide; wherein the composition has a number of drops to tracking at 250 volts of greater than or equal to 50 drops determined according to ASTM D-3638-85.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application of PCT/US16/18870,filed Feb. 22, 2016, which claims the benefit of U.S. ProvisionalApplication No. 62/119,487, filed Feb. 23, 2015, both of which areincorporated by reference in their entirety herein.

BACKGROUND

This disclosure is directed to polyetherimide compositions, and inparticular to electrical tracking resistant polyetherimide compositions,articles formed therefrom, and their methods of manufacture.

Polyetherimides are known as outstanding high performance materials,having a high glass transition temperature (Tg), high modulus andstrength at elevated temperatures, as well as excellent chemicalresistance. They are useful in the manufacture of articles andcomponents for a wide range of applications. Because of their broad use,particularly in the electrical and electronic industries, it isdesirable to provide polyetherimides with good electrical trackingresistance. Electrical tracking is the formation of conductive pathwayson the surface of a polymer under certain conditions and at a certainvoltage. Electrical tracking in a polymer can be a source of firetherefore resistance to electrical tracking is often an important safetyrequirement for a material used in certain electrical applications. Acommon method of reporting the electrical tracking resistance of apolymer is by its comparative tracking index rating (CTI). Currentlyknown polyetherimides can have a comparative tracking index (CTI) of 100to 175 volts. However, some applications can require a material having ahigher CTI.

There accordingly remains a need in the art for polyetherimidecompositions that have excellent electrical tracking resistance. Itwould be a further advantage if the compositions could be renderedelectrical tracking resistant without a significant detrimental effecton one or more of material cost, processability, and mechanicalproperties.

SUMMARY

The above-described and other deficiencies of the art are met by apolyetherimide composition comprising: based on the total weight of thecomposition, 25 wt % to 50 wt % of a polyetherimide; and 50 wt % to 75wt % of a polyphthalamide; wherein the composition has a number of dropsto tracking at 250 volts of greater than or equal to 50 drops determinedaccording to ASTM D-3638-85.

An exemplary composition comprises, based on the total weight of thecomposition, 25 wt % to 60 wt % of a polyetherimide; and 40 wt % to 75wt % of a polyester; wherein the composition has a number of drops totracking at 250 volts of greater than or equal to 50 drops determinedaccording to ASTM D-3638-85.

Another exemplary composition comprises, based on the total weight ofthe composition, 25 wt % to 75 wt % of a polyetherimide; and 25 wt % to75 wt % of an aliphatic polyamide; wherein the composition has a numberof drops to tracking at 250 volts of greater than or equal to 50 dropsdetermined according to ASTM D-3638-85.

In another embodiment, a method of manufacture comprises combining theabove-described components to form a polyetherimide composition.

In yet another embodiment, an article comprises the above-describedpolyetherimide composition.

In still another embodiment, a method of manufacture of an articlecomprises molding, extruding, or shaping the above-describedpolyetherimide composition into an article.

The above described and other features are exemplified by the followingdrawings, detailed description, examples, and claims.

DETAILED DESCRIPTION

The inventors have discovered that the addition of 25 wt % to 75 wt % ofa polymer such as a polyphthalamide, a polyester, an aliphaticpolyamide, or a combination comprising at least one of the foregoing topolyetherimides results in a significant improvement in the electricaltracking resistance of the polyetherimides. The polyetherimidecompositions have a number of drops to tracking at 250 volts of greaterthan or equal to 50 drops determined according to ASTM D-3638-85 and atracking voltage of greater than or equal to 270 volts determinedaccording to ASTM D-3638-85. The polyetherimide compositions can furtherhave balanced mechanical properties such as tensile strength, tensilemodulus, melt flow, or heat deflection temperature.

Polyetherimides comprise more than 1, for example 2 to 1000, or 5 to500, or 10 to 100 structural units of formula (1)

wherein each R is independently the same or different, and is asubstituted or unsubstituted divalent organic group, such as asubstituted or unsubstituted C₆₋₂₀ aromatic hydrocarbon group, asubstituted or unsubstituted straight or branched chain C₂₋₂₀ alkylenegroup, a substituted or unsubstituted C₃₋₈ cycloalkylene group, inparticular a halogenated derivative of any of the foregoing. In someembodiments R is divalent group of one or more of the formulas (2)

wherein Q¹ is —O—, —S—, —C(O)—, —SO₂—, —SO—, —C_(y)H_(2y)— wherein y isan integer from 1 to 5 or a halogenated derivative thereof (whichincludes perfluoroalkylene groups), or —(C₆H₁₀)_(z)— wherein z is aninteger from 1 to 4. In some embodiments R is m-phenylene, p-phenylene,or a diarylene sulfone, in particular bis(4,4′-phenylene)sulfone,bis(3,4′-phenylene)sulfone, bis(3,3′-phenylene)sulfone, or a combinationcomprising at least one of the foregoing. In some embodiments, at least10 mole percent of the R groups contain sulfone groups, and in otherembodiments no R groups contain sulfone groups.

Further in formula (1), T is —O— or a group of the formula —O—Z—O—wherein the divalent bonds of the —O— or the —O—Z—O— group are in the3,3′, 3,4′, 4,3′, or the 4,4′ positions, and Z is an aromatic C₆₋₂₄monocyclic or polycyclic moiety optionally substituted with 1 to 6 C₁₋₈alkyl groups, 1 to 8 halogen atoms, or a combination comprising at leastone of the foregoing, provided that the valence of Z is not exceeded.Exemplary groups Z include groups of formula (3)

wherein R^(a) and R^(b) are each independently the same or different,and are a halogen atom or a monovalent C₁₋₆ alkyl group, for example; pand q are each independently integers of 0 to 4; c is 0 to 4; and X^(a)is a bridging group connecting the hydroxy-substituted aromatic groups,where the bridging group and the hydroxy substituent of each C₆ arylenegroup are disposed ortho, meta, or para (specifically para) to eachother on the C₆ arylene group. The bridging group X^(a) can be a singlebond, —O—, —S—, —S(O)—, —S(O)₂—, —C(O)—, or a C₁₋₁₈ organic bridginggroup. The C₁₋₁₈ organic bridging group can be cyclic or acyclic,aromatic or non-aromatic, and can further comprise heteroatoms such ashalogens, oxygen, nitrogen, sulfur, silicon, or phosphorous. The C₁₋₁₈organic group can be disposed such that the C₆ arylene groups connectedthereto are each connected to a common alkylidene carbon or to differentcarbons of the C₁₋₁₈ organic bridging group. A specific example of agroup Z is a divalent group of formula (3a)

wherein Q is —O—, —S—, —C(O)—, —SO₂—, —SO—, or —C_(y)H_(2y)— wherein yis an integer from 1 to 5 or a halogenated derivative thereof (includinga perfluoroalkylene group). In a specific embodiment Z is a derived frombisphenol A, such that Q in formula (3a) is 2,2-isopropylidene.

In an embodiment in formula (1), R is m-phenylene, p-phenylene, or acombination comprising at least one of the foregoing, and T is —O—Z—O—wherein Z is a divalent group of formula (3a). Alternatively, R ism-phenylene, p-phenylene, or a combination comprising at least one ofthe foregoing, and T is —O—Z—O wherein Z is a divalent group of formula(3a) and Q is 2,2-isopropylidene. Alternatively, the polyetherimide canbe a copolymer comprising additional structural polyetherimide units offormula (1) wherein at least 50 mole percent (mol %) of the R groups arebis(3,4′-phenylene)sulfone, bis(3,3′-phenylene)sulfone, or a combinationcomprising at least one of the foregoing and the remaining R groups arep-phenylene, m-phenylene or a combination comprising at least one of theforegoing; and Z is 2,2-(4-phenylene)isopropylidene, i.e., a bisphenol Amoiety.

In some embodiments, the polyetherimide is a copolymer that optionallycomprises additional structural imide units that are not polyetherimideunits, for example imide units of formula (4)

wherein R is as described in formula (1) and each V is the same ordifferent, and is a substituted or unsubstituted C₆₋₂₀ aromatichydrocarbon group, for example a tetravalent linker of the formulas

wherein W is a single bond, —S—, —C(O)—, —SO₂—, —SO—, or —C_(y)H_(2y)—wherein y is an integer from 1 to 5 or a halogenated derivative thereof(which includes perfluoroalkylene groups). These additional structuralimide units preferably comprise less than 20 mol % of the total numberof units, and more preferably can be present in amounts of 0 to 10 mol %of the total number of units, or 0 to 5 mol % of the total number ofunits, or 0 to 2 mole % of the total number of units. In someembodiments, no additional imide units are present in thepolyetherimide.

The polyetherimide can be prepared by any of the methods known to thoseskilled in the art, including the reaction of an aromatic bis(etheranhydride) of formula (5) or a chemical equivalent thereof, with anorganic diamine of formula (6)

wherein T and R are defined as described above. Copolymers of thepolyetherimides can be manufactured using a combination of an aromaticbis(ether anhydride) of formula (5) and an additional bis(anhydride)that is not a bis(ether anhydride), for example pyromellitic dianhydrideor bis(3,4-dicarboxyphenyl) sulfone dianhydride.

Illustrative examples of aromatic bis(ether anhydride)s include2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (also knownas bisphenol A dianhydride or BPADA),3,3-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride;4,4′-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride;4,4′-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride;4,4′-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride;4,4′-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride;4,4′-bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride;4,4′-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhydride;4,4′-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride;4,4′-bis(2,3-dicarboxyphenoxy)diphenyl sulfone dianhydride;4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)diphenyl-2,2-propanedianhydride; 4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)diphenylether dianhydride;4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)diphenyl sulfidedianhydride;4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)benzophenonedianhydride; 4,4′-(hexafluoroisopropylidene)diphthalic anhydride; and4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)diphenyl sulfonedianhydride. A combination of different aromatic bis(ether anhydride)scan be used.

Examples of organic diamines include 1,4-butane diamine,1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine,1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine,1,12-dodecanediamine, 1,18-octadecanediamine,3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine,4-methylnonamethylenediamine, 5-methylnonamethylenediamine,2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 2,2-dimethylpropylenediamine, N-methyl-bis (3-aminopropyl) amine,3-methoxyhexamethylenediamine, 1,2-bis(3-aminopropoxy) ethane,bis(3-aminopropyl) sulfide, 1,4-cyclohexanediamine,bis-(4-aminocyclohexyl) methane, m-phenylenediamine, p-phenylenediamine,2,4-diaminotoluene, 2,6-diaminotoluene, m-xylylenediamine,p-xylylenediamine, 2-methyl-4,6-diethyl-1,3-phenylene-diamine,5-methyl-4,6-diethyl-1,3-phenylene-diamine, benzidine,3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 1,5-diaminonaphthalene,bis(4-aminophenyl) methane, bis(2-chloro-4-amino-3,5-diethylphenyl)methane, bis(4-aminophenyl) propane, 2,4-bis(p-amino-t-butyl) toluene,bis(p-amino-t-butylphenyl) ether, bis(p-methyl-o-aminophenyl) benzene,bis(p-methyl-o-aminopentyl) benzene, 1, 3-diamino-4-isopropylbenzene,bis(4-aminophenyl) sulfide, bis-(4-aminophenyl) sulfone (also known as4,4′-diaminodiphenyl sulfone (DDS)), and bis(4-aminophenyl) ether. Anyregioisomer of the foregoing compounds can be used. C₁₋₄ alkylated orpoly(C₁₋₄)alkylated derivatives of any of the foregoing can be used, forexample a polymethylated 1,6-hexanediamine. Combinations of thesecompounds can also be used. In some embodiments the organic diamine ism-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenyl sulfone,3,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, or acombination comprising at least one of the foregoing.

The polyetherimides can have a melt index of 0.1 to 10 grams per minute(g/min), as measured by American Society for Testing Materials (ASTM)D1238 at 340 to 370° C., using a 6.7 kilogram (kg) weight. In someembodiments, the polyetherimide has a weight average molecular weight(Mw) of 1,000 to 150,000 grams/mole (Dalton), as measured by gelpermeation chromatography, using polystyrene standards. In someembodiments the polyetherimide has an Mw of 10,000 to 80,000 Daltons.Such polyetherimides typically have an intrinsic viscosity greater than0.2 deciliters per gram (dl/g), or, more specifically, 0.35 to 0.7 dl/gas measured in m-cresol at 25° C.

The amount of polyetherimide used in the polyetherimide composition canvary widely, and is that amount effective to provide the desiredmechanical properties and electrical tracking resistance. In someinstances the polyetherimide is present in an amount from 25 wt % to 75wt %, 25 wt % to 60 wt %, or 25 wt % to 50 wt %, each based on the totalweight of the composition.

The polyetherimide compositions further comprise a polyphthalamide.Polyphthalamides comprise repeating units having formula (7)

wherein each G¹ is independently a branched or unbranched C₄₋₈ alkyl. Insome embodiments, each G¹ is a 1,6-hexyl group. Polyamides, in generalcharacterized by the presence of an amide group (—C(O)NH—) which is thecondensation product of a carboxylic acid and an amine Polyphthalamidesare the condensation product of terephthalic acid and an amine,isophthalic acid and an amine or a combination of terephthalic acid,isophthalic acid and an amine. When employing more than one diamine theratio of the diamines can affect some of the physical properties of theresulting polymer such as the melt temperature. When employing more thanone acid, the ratio of the acids can affect some of the physicalproperties of the resulting polymer as well. The ratio of diamine todicarboxylic acid is typically equimolar although excesses of one or theother can be used to determine the end group functionality. In additionthe reaction can further include monoamines and monocarboxylic acidswhich function as chain stoppers and determine, at least in part, theend group functionality. In some embodiments it is preferable to have anamine end group content of greater than or equal to about 30milllequivalents per gram (meq/g), or, more specifically, greater thanor equal to about 40 meq/g.

In an embodiment the polyphthalamide is a block copolymer or a randomcopolymer comprising the units of formula (7) and units of formula (8)

wherein each G² and G³ are independently a branched or unbranched C₄₋₁₂alkyl group.

In an embodiment, the polyetherimide compositions comprise a nylon,i.e., an aliphatic polyamide. Aliphatic polyamides comprise units offormula (8). Aliphatic polyamides are generally derived from thepolymerization of the corresponding C₄₋₁₂ organic lactams, or C₄₋₁₂amino acids and C₄₋₁₂ carboxylic acids as is known in the art. Examplesof useful nylon 6, nylon 6,6, nylon 4,6, nylon 6, 12, nylon 10, or thelike, or combinations including at least one of the foregoingpolyamides.

The polyetherimide compositions can comprise a polyester. Suitablepolyesters include those comprising structural units of the formula (9)

wherein each R¹ is independently a divalent aliphatic, alicyclic, oraromatic hydrocarbon group, or a combination comprising at least one ofthe foregoing and each A¹ is independently a divalent aliphatic,alicyclic, or aromatic group, or a combination comprising at least oneof the foregoing. Examples of suitable polyesters comprising thestructure of formula (9) are poly(alkylene dicarboxylate)s, liquidcrystalline polyesters, polyarylates, and polyester copolymers such ascopolyestercarbonates and polyesteramides. Also included are polyestersthat have been treated with relatively low levels of diepoxy ormulti-epoxy compounds. It is also possible to use branched polyesters inwhich a branching agent, for example, a glycol having three or morehydroxyl groups or a trifunctional or multifunctional carboxylic acidhas been incorporated. Treatment of the polyester with a trifunctionalor multifunctional epoxy compound, for example, triglycidyl isocyanuratecan also be used to make branched polyester. Furthermore, it issometimes desirable to have various concentrations of acid and hydroxylendgroups on the polyester, depending on the ultimate end-use of thecomposition.

In some embodiments at least some of the polyester comprisesnucleophilic groups such as, for example, carboxylic acid groups. Insome instances, it is desirable to reduce the number of carboxylic endgroups, typically to less than 20 microequivalents per gram ofpolyester, with the use of acid reactive species. In other instances, itis desirable that the polyester has a relatively high carboxylic endgroup concentration, for example 20 to 250 microequivalents per gram ofpolyester or, more specifically, 30 to 100 microequivalents per gram ofpolyester.

In some embodiments, in formula (9) is a C₂₋₁₀ alkylene group, a C₆₋₁₀alicyclic group or a C₆₋₂₀ aromatic group, preferably a C₂₋₆ or a C₂₋₄alkylene group. The A¹ group in formula (9) is most often p- orm-phenylene or a mixture thereof. This class of polyesters includes thepoly(alkylene terephthalates), the poly(alkylene naphthalates) and thepolyarylates. Exemplary poly(alkylene terephthalates) include linearaliphatic polyesters such as poly(ethylene terephthalate) (PET) andpoly(butylene terephthalate) (PBT), as well as cyclic aliphaticpolyesters such as poly(cyclohexanedimethanol terephthalate) (PCT).Exemplary poly(alkylene naphthalate)s includepoly(butylene-2,6-naphthalate) (PBN) and poly(ethylene-2,6-naphthalate)(PEN). Other useful polyesters includepoly(ethylene-co-cyclohexanedimethanol terephthalate) (PETG),polytrimethylene terephthalate (PTT),poly(dimethanol-1,4-cyclohexanedicarboxylate) (PCCD), and polyxyleneterephthalate (PXT). Polyesters are known in the art as illustrated bythe following U.S. Pat. Nos. 2,465,319, 2,720,502, 2,727,881, 2,822,348,3,047,539, 3,671,487, 3,953,394, and 4,128,526.

Liquid crystalline polyesters having melting points less that 380° C.and comprising recurring units derived from aromatic diols, aliphatic oraromatic dicarboxylic acids, and aromatic hydroxy carboxylic acids arealso useful. Examples of useful liquid crystalline polyesters include,but are not limited to, those described in U.S. Pat. Nos. 4,664,972 and5,110,896. Mixtures of polyesters are also sometimes suitable.

The various polyesters can be distinguished by their corresponding glasstransition temperatures (Tg) and melting points (Tm). The liquidcrystalline polyesters generally have a Tg and Tm that are higher thanthe naphthalate-type polyesters. The naphthalate-type polyestersgenerally have a Tg and Tm that are higher than the terephthalate-typepolyesters. Selection of the polyester or combination of polyestersutilized is therefore determined, in part, by the desired propertyprofile required by the ultimate end-use application for thecomposition.

Because of the tendency of polyesters to undergo hydrolytic degradationat the high extrusion and molding temperatures in some embodiments thepolyester is substantially free of water. The polyester can be predriedbefore admixing with the other ingredients. Alternatively, the polyestercan be used without predrying and the volatile materials can be removedby vacuum venting the extruder. The polyesters generally have numberaverage molecular weights in the range of 15,000-100,000, as determinedby gel permeation chromatography (GPC) at 30° C. in a 60:40 by weightmixture of phenol and 1,1,2,2-tetrachloroethane.

The polyetherimide compositions also comprise talc. The amount of talcis in the range of 5 to 20 wt %, or 5 to 15 wt %, based on the totalweight of the polyetherimide compositions.

The particle size of talc also affects the CTI performance of thepolyetherimide compositions. In an embodiment, the titanium dioxide hasa D95 of 2 microns to 6 microns. As used herein, D95 refer to thecut-particle diameter of the particulate where 95 wt % of the particlesin the total distribution of the referenced sample have the notedparticle diameter or smaller. For example, a D95 particle size of 3.5microns means that 95 wt % of the particles in the sample have adiameter of 3.5 microns or less. In an embodiment, the particle size isdetermined by sedigraph analysis using for example a MicromeriticsSedigraph 5120 Particle Size Analysis System.

The polyetherimide compositions can include various additives ordinarilyincorporated into polymer compositions of this type, with the provisothat the additives are selected so as to not significantly adverselyaffect the desired properties of the composition. Exemplary additivesinclude catalysts, impact modifiers, fillers, antioxidants, thermalstabilizers, light stabilizers, ultraviolet light (UV) absorbingadditives, quenchers, plasticizers, lubricants, mold release agents,antistatic agents, visual effect additives such as dyes, pigments, andlight effect additives, flame retardants, anti-drip agents, andradiation stabilizers. Combinations of additives can be used, forexample a combination of a heat stabilizer, a mold release agent, andoptionally an ultraviolet light stabilizer. In an embodiment thepolyetherimide compositions further comprise an additive selected from aprocessing aid, a heat stabilizer, an ultraviolet light absorber, acolorant, a flame retardant, or a combination comprising at least one ofthe foregoing. In general, the additives are used in the amountsgenerally known to be effective. The foregoing additives (except anyfillers) are generally each present in an amount of 0.0001 to 20 wt % or0.005 to 20 wt %, specifically 0.01 to 10 wt %, based on the totalweight of the composition. Alternatively, in some embodiments, thecompositions do not contain appreciable amounts of additives, and insome embodiments, there are no detectable amounts of additives, i.e.,additives are substantially absent or absent from the compositions.Accordingly, the foregoing additives (except any fillers) can be presentin an amount from 0 to 0.1 wt %, 0 to 0.01 wt %, or 0 to 0.001 wt %, or0 to 0.0001 wt %, based on the total weight of the composition. Inanother embodiment, no appreciable amount of any additive other than aheat stabilizer, a mold release agent, and optionally an ultravioletlight stabilizer is present in the compositions. In still anotherembodiment, no detectable amount of any additive other than a heatstabilizer, a mold release agent, and optionally an ultraviolet lightstabilizer is present in the compositions.

Suitable antioxidants can be compounds such as phosphites, phosphonites,and hindered phenols or a combination comprising at least one of theforegoing. Phosphorus-containing stabilizers including triarylphosphites and aryl phosphonates are useful additives. Difunctionalphosphorus containing compounds can also be unseeded. Preferredstabilizers can have a molecular weight greater than 300. Some exemplarycompounds are tris-di-tert-butylphenyl phosphite available from CibaChemical Co. as IRGAFOS 168 and bis (2,4-dicumylphenyl) pentaerythritoldiphosphite available commercially from Dover Chemical Co. as DOVERPHOSS-9228.

Examples of phosphites and phosphonites include: triphenyl phosphite,diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite,diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol diphosphite,diisodecyloxy pentaerythritol diphosphite,bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite,bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristearylsorbitol tri-phosphite, tetrakis(2,4-di-tert-butyl-phenyl)4,4′-biphenylene diphosphonite, bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite, bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite,2,2′,2″-nitrilo[triethyltris(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite],2-ethylhexyl(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphiteand5-butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphirane.

Combinations comprising more than one organophosphorous compound arecontemplated. When used in combination the organo phosphorous compoundscan be of the same type or different types. For example, a combinationcan comprise two phosphite or a combination can comprise a phosphite anda phosphonite. In some embodiments, phosphorus-containing stabilizerswith a molecular weight greater than 300 are useful.Phosphorus-containing stabilizers, for example an aryl phosphite areusually present in the composition in an amount from 0.005 to 3 wt %,specifically 0.01 to 1.0 wt %, based on total weight of the composition.

Hindered phenols can also be used as antioxidants, for example alkylatedmonophenols, and alkylated bisphenols or poly phenols. Exemplaryalkylated monophenols include 2,6-di-tert-butyl-4-methylphenol;2-tert-butyl-4,6-dimethylphenol; 2,6-di-tert-butyl-4-ethylphenol;2,6-di-tert-butyl-4-n-butylphenol; 2,6-di-tert-butyl-4-isobutylphenol;2,6-dicyclopentyl-4-methylphenol;2-(alpha-methylcyclohexyl)-4,6-dimethylphenol;2,6-dioctadecyl-4-methylphenol; 2,4,6-tricyclohexylphenol;2,6-di-tert-butyl-4-methoxymethylphenol; nonyl phenols which are linearor branched in the side chains, for example,2,6-di-nonyl-4-methylphenol;2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol;2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol;2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol or a combination comprisingat least one of the foregoing. Exemplary alkylidene bisphenols include2,2′-methylenebis(6-tert-butyl-4-methylphenol),2,2′-methylenebis(6-tert-butyl-4-ethylphenol),2,2′-methylenebis[4-methyl-6-(alpha-methylcyclohexyl)-phenol],2,2′-methylenebis(4-methyl-6-cyclohexylphenol),2,2′-methylenebis(6-nonyl-4-methylphenol),2,2′-methylenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(4,6-di-tert-butylphenol),2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2′-methylenebis[6-(alpha-methylbenzyl)-4-nonylphenol],2,2′-methylenebis[6-(alpha, alpha-dimethylbenzyl)-4-nonylphenol],4,4′-methylenebis-(2,6-di-tert-butylphenol),4,4′-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene,bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis-(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane,1,1,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane or acombination comprising at least one of the foregoing.

The hindered phenol compound can have a molecular weight of greater than300 g/mole. The high molecular weight can help retain the hinderedphenol moiety in the polymer melt at high processing temperatures, forexample greater than 300° C. Hindered phenol stabilizers, are usuallypresent in the composition in an amount from 0.005 to 2 wt %,specifically 0.01 to 1.0 wt %, based on total weight of the composition.

Examples of mold release agents include both aliphatic and aromaticcarboxylic acids and their alkyl esters, for example, stearic acid,behenic acid, pentaerythritol tetrastearate, glycerin tristearate, andethylene glycol distearate. Polyolefins such as high-densitypolyethylene, linear low-density polyethylene, low-density polyethyleneand similar polyolefin homopolymers and copolymers can also be used amold release agents. Mold release agents are typically present in thecomposition at 0.05 to 10 wt %, based on total weight of thecomposition, specifically 0.1 to 5 wt %. Preferred mold release agentswill have high molecular weight, typically greater than 300, to preventloss of the release agent from the molten polymer mixture during meltprocessing.

In particular, an optional polyolefin can be added to modify thechemical resistance characteristics and mold release characteristics ofthe composition. Homopolymers such as polyethylene, polypropylene,polybutene can be used either separately or in combination. Polyethylenecan be added as high-density polyethylene (HDPE), low-densitypolyethylene (LDPE) or branched polyethylene. Polyolefins can also beused in copolymeric form with compounds containing carbonic acid groupssuch as maleic acid or citric acid or their anhydrides, acid compoundscontaining acrylic acid groups such as acrylic acid ester, and the like,as well as combinations comprising at least one of the foregoing. Whenpresent, the polyolefin, in particular HDPET, is used in an amount frommore than 0 to 10 wt %, specifically 0.1 to 8 wt %, more specificallyfrom 0.5 to 5 wt %, all based on the total weight of the composition.

In some embodiments, the polyetherimide compositions can further includeat least one additional polymer. Examples of such additional polymersinclude and are not limited to PPSU (polyphenylene sulfone),polyetherimides, PSU (polysulfone), PPET (polyphenylene ether), PFA(perfluoroalkoxy alkane), MFA (co-polymer of TFE tetrafluoroethylene andPFVE perfluorinated vinyl ether), FEP (fluorinated ethylene propylenepolymers), PPS (poly(phenylene sulfide), PTFE (polytetrafluoroethylene),PA (polyamide), PBI (polybenzimidizole) and PAI (poly(amide-imide)),poly(ether sulfone), poly(aryl sulfone), polyphenylenes,polybenzoxazoles, polybenzthiazoles, as well as blends and co-polymersthereof. When present, the polymer is used in an amount from more than 0to 20 wt %, specifically 0.1 to 15 wt %, more specifically from 0.5 to10 wt %, all based on the total weight of the composition. In anembodiment, no polymer other than the polyetherimide as described hereinis present in the composition.

Colorants such as pigment and/or dye additives can also optionally bepresent. Useful pigments can include, for example, inorganic pigmentssuch as metal oxides and mixed metal oxides such as zinc oxide, titaniumdioxide, iron oxides, or the like; sulfides such as zinc sulfides, orthe like; aluminates; sodium sulfo-silicates sulfates, chromates, or thelike; carbon blacks; zinc ferrites; ultramarine blue; organic pigmentssuch as azos, di-azos, quinacridones, perylenes, naphthalenetetracarboxylic acids, flavanthrones, isoindolinones,tetrachloroisoindolinones, anthraquinones, enthrones, dioxazines,phthalocyanines, and azo lakes; Pigment Red 101, Pigment Red 122,Pigment Red 149, Pigment Red 177, Pigment Red 179, Pigment Red 202,Pigment Violet 29, Pigment Blue 15, Pigment Blue 60, Pigment Green 7,Pigment Yellow 119, Pigment Yellow 147, Pigment Yellow 150, and PigmentBrown 24; or combinations comprising at least one of the foregoingpigments. Pigments are generally used in amount from 0 to 10 wt %,specifically 0 to 5 wt %, based on the total weight of the composition.In some instances, where improved impact is desired pigments such astitanium dioxide will have a mean particle size of less than 5 microns.

In some instances it is desired to have polyetherimide compositions thatare essentially free of bromine and chlorine. “Essentially free” ofbromine and chlorine means that the composition has less than 3 wt % ofbromine and chlorine, and in other embodiments less than 1 wt % bromineand chlorine by weight of the composition. In other embodiments, thecomposition is halogen free. “Halogen free” is defined as having ahalogen content (total amount of fluorine, bromine, chlorine, andiodine) of less than 1000 parts by weight of halogen per million partsby weight of the total composition (ppm). The amount of halogen can bedetermined by ordinary chemical analysis such as atomic absorption.

The polyetherimide compositions can be prepared by blending theingredients under conditions for the formation of an intimate blend.Such conditions often include melt mixing in single or twin screw typeextruders, mixing bowl, or similar mixing devices that can apply a shearto the components. Twin-screw extruders are often preferred due to theirmore intensive mixing capability and self-wiping capability, over singlescrew extruders. It is often advantageous to apply a vacuum to the blendthrough at least one vent port in the extruder to remove volatileimpurities in the composition. Often it is advantageous to dry the PETand polyimide polymers prior to melting. The melt processing is oftendone at 290 to 340° C. to avoid excessive polymer degradation whilestill allowing sufficient melting to get an intimate polymer mixturefree of any unbelted components. The polymer blend can also be meltfiltered using a 40 to 100 micron candle or screen filter to removeundesirable black specks or other heterogeneous contaminants.

In an exemplary process, the various components are placed into anextrusion compounder to produce a continuous strand that is cooled andthen chopped into pellets. In another procedure, the components aremixed by dry blending, and then fluxed on a mill and comminuted, orextruded and chopped. The composition and any optional components canalso be mixed and directly molded, e.g., by injection or transfermolding techniques. Preferably, all of the components are freed from asmuch water as possible. In addition, compounding is carried out toensure that the residence time in the machine is short; the temperatureis carefully controlled; the friction heat is utilized; and an intimateblend between the components is obtained. The polyetherimidecompositions can then be molded in any equipment conventionally used forpolyetherimide compositions, such as a Newbury or van Dorn typeinjection-molding machine with conventional cylinder temperatures, at250° C. to 320° C., and conventional mold temperatures at 55° C. to 120°C.

As discussed above, the polyetherimide compositions are formulated tohave excellent electrical tracking resistance. In an embodiment, thecompositions have number of drops to tracking at 250 volts greater thanor equal to 50 drops determined according to ASTM D-3638-85.

Shaped, formed, or molded articles comprising the polyetherimidecompositions are also provided. The polyetherimide compositions can bemolded into useful shaped articles by a variety of means such asinjection molding, extrusion, rotational molding, blow molding, andthermoforming. Thus the polyetherimide compositions can be used to forma foamed article, a molded article, a thermoformed article, an extrudedfilm, an extruded sheet, one or more layers of a multi-layer article(e.g. a cap-layer), a substrate for a coated article, or a substrate fora metallized article.

In another embodiment, at least one of the following articles arecontained in or are derived from the compositions encompassed by thisdisclosure: a solar apparatus, an electrical junction box, an electricalconnector, an electrical vehicle charger, an outdoor electricalenclosure, a smart meter enclosure, a smart grid power node, PV(photovoltaic) frame, and miniature circuit breaker (MCB) applications.

The polyetherimide compositions having improved CTI performance andbalanced mechanical properties are further illustrated by the followingnon-limiting examples. All parts and percentages are by weight unlessexplicitly stated otherwise. All temperatures are degrees Celsius unlessexplicitly stated otherwise.

EXAMPLES

The materials used in the Examples are described in Table 1.

TABLE 1 Source, Component Chemical Description Vendor PEI Polyetherimide(ULTEM*) SABIC PBT Polybutylene terephthalate (PBT 315) SABIC PPAPolyphthalamides (ZYTEL* HTN 501) DuPont Nylon 6,6Poly[imino(1,6-dioxohexamethylene) DuPont imnohexamethylene] (ZYTEL*PA66) Jetfine Talc 3CA Talc having a D95 of 3.5 microns IMERYSBlending, Extrusion, and Molding Conditions

Compositions were formed by melt mixing the polyetherimide and PPA orNylon 6,6. Extrusion was carried out in a 2.5-inch twin screw, vacuumvented extruder. The extruder was set at about 300-350° C. The blendswere run at approximately 250 rotations per minute (rpm) under vacuum.Compositions were made in a one pass method. The extrudate was cooled,pelletized, and dried at 150° C. Test samples were injection molded at aset temperature of 340-350° C. and mold temperature of 150-160° C. usinga 30 second cycle time.

Testing Procedures

All molded samples were conditioned for at least 48 hours at 50%relative humidity prior to testing. Properties were measured using ASTMtest methods. Unless specified to the contrary herein, all teststandards are the most recent standard in effect at the time of filingthis application.

Notched Izod impact values were measured at room temperature on 3.2millimeter thick bars as per ASTM D256. Bars were notched prior to ovenaging; samples were tested at room temperature. Results are in Joulesper meter (J/m).

Tensile properties were measured on 3.2 millimeter type I bars as perASTM method D638 at 23° C. with a crosshead speed of 5millimeters/minute. Percent elongation (% Elongation) is reported atbreak (B). Tensile modulus, tensile strength at yield, tensile strengthat break results is reported in MPa (Mega Pascal) or GPa (Giga Pascal).

Melt flow rates (MFR) were measured in accordance with ASTM D1238 at337° C., using a 6.7 kilogram (kg) weight. MFR is reported in grams per10 minutes (g/10 min).

Heat Deflection Temperature (HDT) was measured on 3.2 millimeterinjection molded bar at 1.82 MPa stress according to ASTM D648. HDT isreported in degree Celsius (C).

Electrical tracking resistance tests were performed on a 3 mm squareplaque (6×6 cm) in accordance with the ASTM D-3638. The test can bestarted at any given voltage. At each voltage 5 specimens are tested andthe average number of drops is recorded. The test is performed at (atleast) 4 different voltages, where there should be at least two datapoints with an average number of drops higher than 50 and two datapoints with an average number of drops lower than 50. A voltageextrapolation to 50 drops is made, and based on this voltage (V_(ASTM))a PLC class is assigned. This assignment is provided according to thetable below. The CTI rating of a polymer indicates how resistant thepolymeric material is to electrical tracking at certain voltages. CTIratings range from CTI-0 to CTI-5 with a CTI-1 rating indicating that apolymer is more resistant to electrical tracking than a polymer with alower CTI rating (for example CTI-3).

VASTM PLC <100 5 100-174 4 175-249 3 250-399 2 400-599 1 ≥600 0

A screening method was employed to predict the CTI-2 performance ofpolyetherimide compositions. The method employed the ASTM D-3638 methodbut testing was conducted at only one voltage, 250 V. The number ofdrops until failure was recorded and no more than 100 drops wereapplied. A prediction of a CTI-2 rating for a sample was based onreaching at least 50 drops of the electrolyte solution before failure at250 V. A prediction of not receiving a CTI rating was based on failurebefore reaching 50 drops of the electrolyte solution at 250 V. Thescreening method for predicting CTI-2 rating is identified throughoutthe disclosure as the CTI test.

Examples 1-4

Examples 1-4 demonstrate the effect of the addition of various amountsof PPA in the polyetherimide compositions on mechanical and CTIproperties. Formulations and results are shown in table 2.

TABLE 2 1 2 3* 4* Component PEI 25 40 60 75 PPA 75 60 40 25 PropertyTensile strength (MPa) 70 72 88 71 Tensile modulus (GPa) 2982 3031 31283090 % Elongation 3 3 5 28 Flexural strength (GPa) 123 131 149 155Flexural Modulus (MPa) 2962 2958 3186 3203 MFR 337° C., 6.7 Kg, 5 min —52.4 23.7 5.6 (g/10 min) Notched Impact (J/m) 52 50 44 44 HDT (1.82 MPa)115 114 134 169 No. of drops for tracking@ 250 Volts 100 100 31 19 PLCrating 2 2 3 3 *Comparative Example

These examples demonstrate that blending greater than 50 wt % to lessthan or equal to 75 wt % of PPA with PEI provides a composition capableof achieving a combination of a tensile strength greater than or equalto 70 MPa, tensile modulus greater than equal to 2900 GPa, melt flowrate greater than or equal to 50 g/10 minutes, HDT greater than or equalto 110° C., number of drops to tracking at 250 volts greater than orequal to 50 drops, and notched Izod impact strength greater than orequal to 45 J/m.

Examples 5-10

Examples 5-10 demonstrate the effect of the addition of differentamounts of Nylon 6,6 in polyetherimide compositions on mechanical andCTI properties. Formulations and results are shown in Table 3.

TABLE 3 5 6 7 8* 9 10 Component PEI 25 40 60 75 50 47 Nylon 6,6 75 60 4025 33 53 Jet fine Talc 3 CA 17 15 Property Tensile strength (MPa) 72 8079 94 79 71 Tensile modulus (GPa) 3018 2923 2979 3040 4127 4438 %Elongation 4 7 4 6 4 4 Flexural strength (GPa) 107 117 124 141 139 128Flexural Modulus (MPa) 2582 2763 2840 2974 4161 4534 MFR 337° C., 20 1311 6 8 3 6.7 Kg, 5 min (g/10 min) HDT (1.82 MPa) 75 108 152 174 170 164No. of drops for 100 100 100 13 100 93 tracking@ 250 Volts *ComparativeExample

These examples demonstrate that blending greater than 25 wt % to lessthan or equal to 75 wt % of Nylon 6,6 with PEI provides a compositioncapable of achieving a combination of a tensile strength greater than orequal to 70 MPa, tensile modulus greater than equal to 2900 GPa, meltflow rate greater than or equal to 3 g/10 minutes, HDT greater than orequal to 75° C., and number of drops to tracking at 250 volts greaterthan or equal to 50 drops. The data shows that addition of talc improvesthe heat properties of the composition (example 9) as shown by HDT data(170° C.).

Examples 11-14

Examples 11-14 demonstrate the effect of the addition of various amountsof PBT to polyetherimide compositions on tensile strength, tensilemodulus, and CTI properties. Formulations and results are shown in table4.

TABLE 4 11 12 13 14* Component PEI 25 40 60 75 PBT 75 60 40 25 Jet fineTalc 3CA Property Tensile strength (MPa) 59 70 50 101 Tensile modulus(GPa) 2689 2546 2968 3075 % Elongation 3 37 2 4 Flexural strength (GPa)90 98 74 141 Flexural Modulus (MPa) 2362 2324 2683 2987 MFR 337° C., 6.7Kg, 5 min (g/10 min) 215 21 11.2 3.5 HDT (1.82 MPa) 72 65 92 119 No. ofdrops for tracking@ 250 Volts 69 100 100 5 *Comparative Example

These examples demonstrate that blending greater than or equal to 40 wt% to less than or equal to 75 wt % of PET with PEI provides acomposition capable of achieving a combination of a tensile strengthgreater than or equal to 50 MPa, tensile modulus greater than equal to2500 GPa, melt flow rate greater than or equal to 10 g/10 minutes, HDTgreater than or equal to 60° C., and number of drops to tracking at 250volts greater than or equal to 50 drops.

Set forth below are specific embodiments of polyetherimide compositions,methods of manufacture and articles comprising the same.

In an embodiment, a composition comprises, based on the total weight ofthe composition, 25 wt % to 50 wt % of a polyetherimide; and 50 wt % to75 wt % of a polyphthalamide; wherein the composition has a number ofdrops to tracking at 250 volts of greater than or equal to 50 dropsdetermined according to ASTM D-3638-85. One or more of the followingconditions can apply: the polyphthalamide comprises units of the formula(7) wherein Q¹ is independently at each occurrence a branched orunbranched alicyclic alkyl group having 4 to 8 carbons, preferably Q¹ isindependently at each occurrence a 1,6-hexyl group; the composition hasa tensile strength greater than or equal to 60 MPa determined accordingto ASTM D638, a tensile modulus greater than equal to 2500 GPadetermined according to ASTM D638, and notched Izod impact strengthgreater than or equal to 45 J/m measured at room temperature on 3.2millimeter thick bars as per ASTM D256; or the composition has heatdefection temperature of greater than or equal to 110° C. measured on3.2 millimeter injection molded bar at 1.82 MPa stress according to ASTMD648.

An exemplary composition comprises, based on the total weight of thecomposition, 25 wt % to 60 wt % of a polyetherimide; and 40 wt % to 75wt % of a polyester; wherein the composition has a number of drops totracking at 250 volts of greater than or equal to 50 drops determinedaccording to ASTM D-3638-85. One or more of the following conditions canapply: the polyester is a linear aliphatic polyester; the polyestercomprises poly(ethylene terephthalate) and poly(butylene terephthalate),or a combination comprising at least one of the foregoing; thecomposition has a tensile strength greater than or equal to 40 MPadetermined according to ASTM D638, a tensile modulus greater than equalto 2200 GPa determined according to ASTM D638; or the composition has aheat deflection temperature greater than or equal to 50° C. measured on3.2 millimeter injection molded bar at 1.82 MPa stress according to ASTMD648.

Another exemplary composition comprises, based on the total weight ofthe composition, 25 wt % to 75 wt % of a polyetherimide; and 25 wt % to75 wt % of an aliphatic polyamide; wherein the composition has a numberof drops to tracking at 250 volts of greater than or equal to 50 dropsdetermined according to ASTM D-3638-85. One or more of the followingconditions can apply: the aliphatic polyamide comprises units of theformula (8) wherein each G² and G³ is independently a branched orunbranched C₄₋₁₂ alkyl group; the composition has a tensile strengthgreater than or equal to 60 MPa determined according to ASTM D638, atensile modulus greater than equal to 2500 GPa determined according toASTM D638; or the composition has heat deflection temperature greaterthan or equal to 65° C. measured on 3.2 millimeter injection molded barat 1.82 MPa stress according to ASTM D648.

For any of the foregoing embodiments, the polyetherimide comprises unitsof the formula (1) wherein R is the same or different, and is asubstituted or unsubstituted divalent organic group, T is —O— or a groupof the formula —O—Z—O— wherein the divalent bonds of the —O— or the—O—Z—O— group are in the 3,3′, 3,4′, 4,3′, or the 4,4′ positions; andwherein Z is an aromatic C₆₋₂₄ monocyclic or polycyclic moietyoptionally substituted with 1 to 6 C₁₋₈ alkyl groups, 1 to 8 halogenatoms, or a combination thereof, provided that the valence of Z is notexceeded, preferably R is a divalent group of the formula (2) wherein Q¹is —O—, —S—, —C(O)—, —SO₂—, —SO—, —C_(y)H_(2y)— wherein y is an integerfrom 1 to 5 or a halogenated derivative thereof, or —(C₆H₁₀)_(z)—wherein z is an integer from 1 to 4, and Z is a divalent group of theformula (3a) wherein Q is —O—, —S—, —C(O)—, —SO₂—, —SO—, or—C_(y)H_(2y)— wherein y is an integer from 1 to 5 or a halogenatedderivative thereof, more preferably R is m-phenylene and Q isisopropylidene.

Optionally the foregoing compositions further comprises 5 wt % to 20 wt% of talc.

In an embodiment, an insulating material comprises the composition ofany one of the foregoing embodiments.

Also disclosed is an article selected from a molded article, athermoformed article, an extruded film, an extruded sheet, one or morelayers of a multi-layer article, a substrate for a coated article, and asubstrate for a metallized article made from the composition of any oneof the foregoing embodiments.

A method of manufacture of an article comprises molding, extruding, orcasting the composition of any one of the foregoing embodiments to formthe article.

A method of controlling the tracking of an electrical current of anarticle of manufacture comprises providing a composition of any one ofthe foregoing embodiments and processing the composition to form anarticle of manufacture.

For any of the foregoing articles or methods, the article is a solarapparatus, an electrical junction box, an electrical connector, anelectrical vehicle charger, an outdoor electrical enclosure, a smartmeter enclosure, a smart grid power node, a photovoltaic frame and aminiature circuit breaker.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise. “Or” means “and/or.” Theendpoints of all ranges directed to the same component or property areinclusive and independently combinable. Unless defined otherwise,technical and scientific terms used herein have the same meaning as iscommonly understood by one of skill in the art to which this inventionbelongs.

As used herein, a “combination” is inclusive of blends, mixtures,alloys, reaction products, and the like. Compounds are described usingstandard nomenclature. For example, any position not substituted by anyindicated group is understood to have its valency filled by a bond asindicated, or a hydrogen atom. A dash (“-”) that is not between twoletters or symbols is used to indicate a point of attachment for asubstituent. For example, —CHO is attached through carbon of thecarbonyl group.

The term “alkyl” includes branched or straight chain, unsaturatedaliphatic C₁₋₃₀ hydrocarbon groups e.g., methyl, ethyl, n-propyl,i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, s-pentyl, n- and s-hexyl,n- and s-heptyl, and, n- and s-octyl. “Alkenyl” means a straight orbranched chain, monovalent hydrocarbon group having at least onecarbon-carbon double bond (e.g., ethenyl (—HC═CH₂)). “Alkoxy” means analkyl group that is linked via an oxygen (i.e., alkyl-O—), for examplemethoxy, ethoxy, and sec-butyloxy groups. “Alkylene” means a straight orbranched chain, saturated, divalent aliphatic hydrocarbon group (e.g.,methylene (—CH₂—) or, propylene (—(CH₂)₃—)). “Cycloalkylene” means adivalent cyclic alkylene group, —C_(n)H_(2n-x), wherein x represents thenumber of hydrogens replaced by cyclization(s). The term “aryl” means anaromatic hydrocarbon group containing the specified number of carbonatoms, such as to phenyl, tropone, indanyl, or naphthyl. The prefix“hetero” means that the compound or group includes at least one ringmember that is a heteroatom (e.g., 1, 2, or 3 heteroatom(s)), whereinthe heteroatom(s) is each independently N, O, S, or P.

“Substituted” means that the compound or group is substituted with atleast one (e.g., 1, 2, 3, or 4) substituents instead of hydrogen, whereeach substituent is independently nitro (—NO₂), cyano (—CN), hydroxy(—OH), halogen, thiol (—SH), thiocyano (—SCN), C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₁₋₆ haloalkyl, C₁₋₉ alkoxy, C₁₋₆ haloalkoxy, C₃₋₁₂cycloalkyl, C₅₋₁₈ cycloalkenyl, C₆₋₁₂ aryl, C₇₋₁₃ arylalkylene (e.g,benzyl), C₇₋₁₂ alkylarylene (e.g, toluyl), C₄₋₁₂ heterocycloalkyl, C₃₋₁₂heteroaryl, C₁₋₆ alkyl sulfonyl (—S(═O)₂-alkyl), C₆₋₁₂ arylsulfonyl(—S(═O)₂-aryl), or tosyl (CH₃C₆H₄SO₂—), provided that the substitutedatom's normal valence is not exceeded, and that the substitution doesnot significantly adversely affect the manufacture, stability, ordesired property of the compound. When a compound is substituted, theindicated number of carbon atoms is the total number of carbon atoms inthe group, including those of the substituent(s).

All references cited herein are incorporated by reference in theirentirety. While typical embodiments have been set forth for the purposeof illustration, the foregoing descriptions should not be deemed to be alimitation on the scope herein. Accordingly, various modifications,adaptations, and alternatives can occur to one skilled in the artwithout departing from the spirit and scope herein.

What is claimed is:
 1. A composition comprising, based on the totalweight of the composition, 25 wt % to 40 wt % of a polyetherimide; and60 wt % to 75 wt % of a polyphthalamide; wherein the composition has anumber of drops to tracking at 250 volts of greater than or equal to 50drops determined according to ASTM D-3638-85, and the polyphthalamidecomprises units of the formula

wherein each G¹ is a C6 alkylene group, and wherein the polyetherimidecomprises units of the formula

R is m-phenylene, and T is —O—Z—O— wherein Z is a divalent group offormula

and Q is 2,2-isopropylidene, and the composition is free of aliphaticpolyamides.
 2. The composition of claim 1, wherein the composition has atensile strength greater than or equal to 60 MPa determined according toASTM D638, a tensile modulus greater than equal to 2500 GPa determinedaccording to ASTM D638, and notched Izod impact strength greater than orequal to 45 Jim measured at room temperature on 3.2 millimeter thickbars as per ASTM D256.
 3. The composition of claim 1, wherein thecomposition has heat defection temperature of greater than or equal to110° C. measured on 3.2 millimeter injection molded bar at 1.82 MPastress according to ASTM D648.
 4. The composition of claim 1, furthercomprising 5 wt % to 20 wt % of talc.
 5. An insulating materialcomprising the composition of claim
 1. 6. An article selected from amolded article, a thermoformed article, an extruded film, an extrudedsheet, one or more layers of a multi-layer article, a substrate for acoated article, and a substrate for a metallized article made from thecomposition of claim
 1. 7. An article made from the composition of claim1, wherein the article is a solar apparatus, an electrical junction box,an electrical connector, an electrical vehicle charger, an outdoorelectrical enclosure, a smart meter enclosure, a smart grid power node,a photovoltaic frame and a miniature circuit breaker.
 8. A method ofmanufacture of an article, comprising molding, extruding, or casting thecomposition of claim 1 to form the article.
 9. A method of controllingthe tracking of an electrical current of an article of manufacture, themethod comprising: providing a composition of claim 1, and processingthe composition to form an article of manufacture.
 10. The method ofclaim 9, wherein the article is a solar apparatus, an electricaljunction box, an electrical connector, an electrical vehicle charger, anoutdoor electrical enclosure, a smart meter enclosure, a smart gridpower node, a photovoltaic frame and a miniature circuit breaker. 11.The composition of claim 1 consisting essentially of the polyetherimide;and the polyphthalamide.